This is what I'm thinking of:
There's a sweetish yeast bread with a vanilla pastry cream filling. In Japanese, they're called クリームパン (sometimes transliterated as "cream pan"). The Japanese edition of Wikipedia says that the English is "Custard Filled Brioches", but "Custard Filled Brioches" got 2,700 google hits, versus 22,500 for "Custard Brioche". Is the latter the most common term for the dish?